Weight percentage of nitrogen can be calculated using the following rule:
weight percentage of nitrogen = (weight of nitrogen / weight of urea) x 100
From the periodic table:
molecular mass of carbon = 12 grams
molecular mass of nitrogen = 14 grams
molecular mass of hydrogen = 1 grams
molecular mass of oxygen = 16 grams
therefore:
mass of nitrogen in urea = 2(14) = 28 grams
mass of urea = 12 + 2(14) + 4(1) + 16 = 60 grams
Substitute with the masses in the equation to get the percentage:
weight percentage of nitrogen = (28/60) x 100 = 46.667%
Answer:
The molar mass of unknown gas is 145.82 g/mol.
Explanation:
Volume of oxygen gas effused under time t = 8.24 mL
Effusion rate of oxygen gas = 
Molar mass of oxygen gas = 32 g/mol
Volume of unknown gas effused under time t = 3.86 mL
Effusion rate of unknown gas = 
Molar mass of unknown gas = M
Graham's Law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows the equation:




Mechanical energy of a body is simply the combination of its kinetic energy and potential energy
Answer:Prophase is the first stage of mitosis. In prophase,
Explanation:
Answer:
Polycyclic aromatic hydrocarbons (from petroleum)
Explanation:
Polycyclic aromatic hydrocarbons (PAH) is a group of compounds which contain more than one aromatic ring. Typically examples include; naphthalene, anthracene, phenanthrene etc.
PAH are present in petroleum products. Almost everyone is regularly exposed to vehicles or other equipments that uses petroleum products as fuel. PAH is usually released from the combustion engine of these equipments and may be inhaled by humans. Thus there is a very high risk of PAH exposure compared to other items listed in the question.
PAHs are known to cause different kinds of cancer and other types of health issues in the body. The most disturbing toxicity of PAH is its carcinogenicity which makes it a very serious potential health risk for humans exposed to it on regular basis.